Displaying publications 301 - 320 of 1097 in total

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  1. An evaluation of fermentation period and discs rotation speed of rotary discs reactor for bacterial cellulose production
    Khairul Azly Zahan, Norhayati Pa’e, Ida Idayu Muhamad
    Sains Malaysiana, 2016;45:393-400.
    Acetobacter xylinum strains are known as efficient producers of cellulose. A. xylinum is an obligate aerobic bacterium that has an oxygen-based metabolism. The dissolved oxygen (DO) concentration in a rotary discs reactor (RDR) is one of the most important factors that need to be observed during the cellulose synthesis by these bacteria. In this study, the effects of different discs rotation speed (5, 7, 9 and 12 rpm) and fermentation period (3, 4, 5 and 6 days) on the DO concentration and production of bacterial cellulose in a 10-L RDR were examined. The highest yield was obtained at 7 rpm with a total dried weight of 28.3 g for 4 days fermentation. The results showed that the DO concentration in the 10-L RDR increased in the range of 13 to 17% with increasing of discs rotation speed from 7 to 12 rpm. However, fermentation with high discs rotation speed at 12 rpm reduced the bacterial cellulose production. Analysis of data using Statistica 8.0 showed a high coefficient of determination value (R2 = 0.92). In conclusion, discs rotation speed gave more significant effect on the DO concentration and production of bacterial cellulose in 10-L RDR compared to fermentation period. This was further combined with synergistic effect from sufficient consumption of oxygen for the enhanced production of bacterial cellulose and providing the controlled environment for encouraging bacterial growth throughout the fermentation process.
    Matched MeSH terms: Oxygen
  2. Surface analysis of marine sulphate-reducing bacteria exopolymers on steel during biocorrosion using x-ray photoelectron spectroscopy
    Fathul Karim Sahrani, Madzlan Abd. Aziz, Zaharah Ibrahim, Adibah Yahya
    Sains Malaysiana, 2008;37.
    The aim of this study was to determine the surface chemistry during biocorrosion process on growth and on the production of exopolymeric substances (EPS) in batch cultures of mix-strains of marine sulphate-reducing bacteria (SRB) isolated from Malaysian Shipyard and Engineering Harbours, Pasir Gudang. The EPS and precipitates were analyzed by x-ray photoelectron spectroscopy (XPS). The XPS results indicate that Fe(2p3/2) spectrum for iron sulphide can be fitted with Fe(II) and Fe(III) components, both corresponding to Fe-S bond types. The absence of oxide oxygen in the O(1s) spectrum and Fe(III)-O bond types in the Fe(2p3/2) spectrum supports the conclusion that iron sulphides are composed of both ferric and ferrous iron coordinated with monosulphide and disulphide.
    Matched MeSH terms: Oxygen
  3. Nitridation of Al-Mg-Si alloys through dynamic heating
    Roslinda Shamsudin, Abdul Razak Daud, Muhammad Azmi Abdul Hamid, Saiful Rizam Shamsudin
    Sains Malaysiana, 2007;36:195-200.
    Nitridation behaviour of Al-Mg-Si alloys was studied as a function of temperature by means of thermogravimetry method. A reactive gas, N2-4%H2 at a rate of 10 ml/min was purged into the thermogravimetry analyser chamber. The Al alloys were heated from 25oC to 625oC at the heating rate of 15oC/min and then reduced to 3oC/min until it reached 1500oC. It was found that by varying the amount of Mg and Si in Al-Mg-Si alloys significantly influenced the growth of the composites. A differential thermogravimetric curve shows the Mg containing alloys experienced many steps of chemical reactions. This indicates that besides AlN presence as a major phase, other compounds also exist in the final product. The X-ray diffraction results confirmed the existence of oxide phases such as a-Al2O3, MgAl2O4 and MgO in addition to residual Si and Al metal. The presence of oxide compounds is believed to be due to the reaction between the alloying elements and residual oxygen gas left in the reaction atmosphere. It was also found that Si could play a role in promoting the weight gain of the composite produced. The heating rate has also a profound effect on the weight gain, whereby higher heating rate resulted in low yielded of AlN during the nitridation reaction of the Al-Mg-Si alloys.
    Matched MeSH terms: Oxygen
  4. Effects of thermal stratification on the concentration of iron and manganese in a tropical water supply reservoir
    Noor Halini Baharim, Razali Ismail, Mohamad Hanif Omar
    Sains Malaysiana, 2011;40:1179-1186.
    Thermal stratification in lakes is an important natural process that can have a significant effect on the water resource quality. The potential changes in chemical contents in water resulting from stratification are the production of ammonia, sulphides and algal nutrients and the increasing concentrations of iron and manganese. One of the water supply reservoirs located in Johor, Malaysia facing with high iron and manganese concentrations associated with the period of stratifications. This study showed that the level of thermal stratification in the reservoir varied at different time of the year. During the strongest period of stratification, the dissolved oxygen content was found to diminish significantly with depth and iron and manganese were recorded at the highest concentrations. Although significant period of rainfalls contributed to the natural destratification of reservoir, lower concentrations of iron and manganese only remained for a shorter period before the concentrations continued to increase with the onset of the thermal stratification. A good understanding on the behaviour of the reservoir may help to identify several measures for the improvement of water quality.
    Matched MeSH terms: Oxygen
  5. Fish diversity and water quality during flood mitigation works at Semariang mangrove area, Kuching, Sarawak, Malaysia
    Nyanti L, Nur 'Asikin R, Ling T, Jongkar G
    Sains Malaysiana, 2012;41:1517-1525.
    This study aimed to document the fish diversity and water quality at Semariang mangrove area, Kuching, Sarawak, which is located at the eastern part of Kuching Wetland National Park. Field samplings were carried out in 2009 during the construction of the flood mitigation channel at the eastern part of the park. A total of 21 families represented by 37 species of fish were caught from the area. The six dominant families in terms of the number of individuals caught were Mugilidae (16%), Leiognathidae (16%), Ambassidae (11%), Ariidae (9%), Lutjanidae (8%) and Plotosidae (6%). In terms of the percentage of six dominant genera based on the number of individuals caught, 16% was represented by Valamugil, 11% by Ambassis, 10% by Gazza, 9% by Arius, 8% by Lutjanus and 6% by Plotosus. The values of diversity and richness indices were lower at stations located close to the flood mitigation channel. Similarly, the concentrations of dissolved oxygen were lower and total suspended solids were significantly higher at stations close to the channel and sand mining area. Therefore, fish fauna and water quality at Semariang mangrove area were affected during the construction of the flood mitigation channel.
    Matched MeSH terms: Oxygen
  6. Characterisation of Aciplex Membrane by X-ray Photoelectron Spectroscopy
    Abu Bakar Mohamad, Wan Ramli Wan Daud, Amir Kadhum, Fathi Messaud, Mohd. Ambar Yarmo
    Sains Malaysiana, 1997;26.
    Chemical structure of treated and untreated Aciplex membrane has been studied by X-ray Photoelectron Spectroscopy (XPS). Survey spectra showed that both membrane surfaces consist of Fluorine, Carbon, Oxygen, Sulphur and trace of Titanium. Binding energies for the elements are (C1s at 290.6 eV, F1s at 687.5 eV, O1s at 531.3 eV, S2P at 168.1 eV and Ti2P at 454.4 eV). Analysis of narrow scan XPS-spectra of each element demonstrate the presence of (-CF, -CF2, CF3, C-O-C and SO-3) groups, which are in agreement with the structural formula as disclosed by the manufacturer. There is no significant change in chemical states of untreated and treated membrane, which reflect its stability to treatment conditions.
    Struktur kimia Aciplex membran yang sudah dibersihkan dan yang belum dibersihkan telah dikaji menggunakan Spektroskopi Fotoelektron Sinaran-X (XPS). Spektra yang telah ditinjau menunjukkan bahawa kedua-dua permukaan membran mengandungi Florin, Karbon, Oksigen, Sulfur dan sedikit Titanium. Tenaga ikatan bagi unsur-unsur tersebut adalah (C1s pada 290.6 eV, F1s pada 687.5 eV. O1s pada 531.3 eV, S2P pada 168.2 eV dan Ti2P pada 454.4 eV). Analisis imbasan kecil spektra-xps bagi setiap unsur menunjukkan kehadiran kilmpulan (-CF, - CF2, CF3, C-O-C dan SO-3) yang bertepatan dengan formula struktur dari pihak pembekal. Tiada terdapat perubahan nyata berhubung dengan keadaan kimia membran yang sudah dibersihkan dan yang belum dibersihkan yang menggambarkan kestabilannya terhadap keadaan pembersihan.
    Matched MeSH terms: Oxygen
  7. Microbial fuel cells using mixed cultures of wastewater for electricity generation
    Zain S, Roslani N, Hashim R, Anuar N, Suja F, Basri N, et al.
    Sains Malaysiana, 2011;40.
    Fossil fuels (petroleum, natural gas and coal) are the main resources for generating electricity. However, they have been major contributors to environmental problems. One potential alternative to explore is the use of microbial fuel cells (MFCs), which generate electricity using microorganisms. MFCs uses catalytic reactions activated by microorganisms to convert energy preserved in the chemical bonds between organic molecules into electrical energy. MFC has the ability to generate electricity during the wastewater treatment process while simultaneously treating the pollutants. This study investigated the potential of using different types of mixed cultures (raw sewage, mixed liquor from the aeration tank & return waste activated sludge) from an activated sludge treatment plant in MFCs for electricity generation and pollutant removals (COD & total kjeldahl nitrogen, TKN). The MFC in this study was designed as a dual-chambered system, in which the chambers were separated by a NafionTM membrane using a mixed culture of wastewater as a biocatalyst. The maximum power density generated using activated sludge was 9.053 mW/cm2, with 26.8% COD removal and 40% TKN removal. It is demonstrated that MFC offers great potential to optimize power generation using mixed cultures of wastewater.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  8. Characterization of slowly-biodegradable organic compounds and hydrolysis kinetics in tropical wastewater for biological nitrogen removal
    How SW, Sin JH, Wong SYY, Lim PB, Mohd Aris A, Ngoh GC, et al.
    Water Sci Technol, 2020 Jan;81(1):71-80.
    PMID: 32293590 DOI: 10.2166/wst.2020.077
    Many developing countries, mostly situated in the tropical region, have incorporated a biological nitrogen removal process into their wastewater treatment plants (WWTPs). Existing wastewater characteristic data suggested that the soluble chemical oxygen demand (COD) in tropical wastewater is not sufficient for denitrification. Warm wastewater temperature (30 °C) in the tropical region may accelerate the hydrolysis of particulate settleable solids (PSS) to provide slowly-biodegradable COD (sbCOD) for denitrification. This study aimed to characterize the different fractions of COD in several sources of low COD-to-nitrogen (COD/N) tropical wastewater. We characterized the wastewater samples from six WWTPs in Malaysia for 22 months. We determined the fractions of COD in the wastewater by nitrate uptake rate experiments. The PSS hydrolysis kinetic coefficients were determined at tropical temperature using an oxygen uptake rate experiment. The wastewater samples were low in readily-biodegradable COD (rbCOD), which made up 3-40% of total COD (TCOD). Most of the biodegradable organics were in the form of sbCOD (15-60% of TCOD), which was sufficient for complete denitrification. The PSS hydrolysis rate was two times higher than that at 20 °C. The high PSS hydrolysis rate may provide sufficient sbCOD to achieve effective biological nitrogen removal at WWTPs in the tropical region.
    Matched MeSH terms: Oxygen
  9. Hydrological change effects on sungai langat water quality
    Marina Zainal Abidin, Ahmad Abas Kutty, Tukimat Lihan, Nurul Akhma Zakaria
    Sains Malaysiana, 2018;47:1401-1411.
    This study attempts to assess the impact of various types of land use along Sungai Langat and describes hydrological
    change and water quality variation along this river. This study also determines water quality of Sungai Langat based on
    low flow dry period Q100,7 using the application of QUAL2K. Dissolved oxygen (DO), pH, temperature and conductivity
    were measured in situ. Biochemical oxygen demand (BOD5
    ), ammonia nitrogen (NH3
    -N) and total suspended solid (TSS)
    were analysed according to the standard methods (APHA). Water quality data was referred to National Water Quality
    Standards for Malaysia (NWQS) proposed by Malaysian Department of Environment (DOE) to estimate Sungai Langat
    water quality status. Four important water quality parameters namely DO, BOD5, NH3
    -N and TSS were simulated with
    QUAL2K version 2.07 for 83.67 km. As regard to individual parameter, DO classified this river into class III, BOD5 in
    Class II, NH3
    -N in Class IV and TSS in Class I. Based on QUAL2K simulation for low flow scenario, the results clearly
    demonstrates a gradually reduction of DO and BOD5 whereas NH3
    -N and TSS display opposite. Only NH3
    -N was found
    significantly increase which cause low water quality class towards the downstream. Three parameters namely DO, BOD5
    and NH3
    -N show effects of industrial which approximately located at the middle of river stretch. The TSS was contributed
    to the river system at the upstream and downstream of the river stretch which most likely from sand mining activity which
    located at Sungai Long, Cheras (near R5) and Sungai Semenyih (R11).
    Matched MeSH terms: Oxygen
  10. Fulltext Ultraviolet A and Ultraviolet C Light-Induced Reduction of Surface Hydrocarbons on Titanium Implants
    Naauman Z, Rajion ZAB, Maliha S, Hariy P, Muhammad QS, Noor HAR
    Eur J Dent, 2019 Feb;13(1):114-118.
    PMID: 31170762 DOI: 10.1055/s-0039-1688741
    OBJECTIVE: The carbon, titanium, and oxygen levels on titanium implant surfaces with or without ultraviolet (UV) pretreatment were evaluated at different wavelengths through X-ray photoelectron spectroscopy (XPS).

    MATERIALS AND METHODS: This interventional experimental study was conducted on nine Dio UFII implants with hybrid sandblasted and acid-etched (SLA) surface treatments, divided equally into three groups. Control group A samples were not given UV irradiation, while groups B and C samples were given UVA (382 nm, 25 mWcm2) and UVC (260 nm, 15 mWcm2) irradiation, respectively. The atomic ratio of carbon, titanium, and oxygen was compared through XPS.

    RESULTS: Mean carbon-to-titanium ratio and C1 peaks considerably increased in Group A compared to those in experimental Groups B and C. The intensity of Ti2p and O1s peaks was more pronounced for group C compared to that for groups A and B.

    CONCLUSIONS: Although the decrease in surface hydrocarbons was the same in both UV-treated groups, the peak intensity of oxygen increased in the UVC-treated group. Thus, it can be concluded that compared with UVA irradiation, UVC irradiation has the potential to induce more hydrophilicity on SLA-coated implants.

    Matched MeSH terms: Oxygen
  11. Influence of air supply velocity on temperature field in the self heating process of coa
    Shuanglin Song, Shugang Wang, Yuntao Liang, Xiaochen Li, Qi Lin
    Sains Malaysiana, 2017;46:2143-2148.
    The air supply velocity is an important factor affecting the spontaneous combustion of coal. The appropriate air velocity can not only provide the oxygen required for the oxidation reaction, but maintains the good heat storage environment. Therefore, it is necessary to study the influence of the actual air velocity in the pore space on the self-heating process of coal particles. This paper focuses on studying the real space piled up by spherical particles. CFD simulation software is used to establish the numerical model from pore scale. Good fitness of the simulation results with the existing results verifies the feasibility of the calculation method. Later, the calculation conditions are changed to calculate and analyze the velocity field and the temperature field for self-heating of some particles (the surface of the particles is at a certain temperature) and expound the effect of different air supply velocities on gathering and dissipating the heat.
    Matched MeSH terms: Oxygen
  12. Fulltext Oxygen-Releasing Antibacterial Nanofibrous Scaffolds for Tissue Engineering Applications
    Abudula T, Gauthaman K, Hammad AH, Joshi Navare K, Alshahrie AA, Bencherif SA, et al.
    Polymers (Basel), 2020 May 29;12(6).
    PMID: 32485817 DOI: 10.3390/polym12061233
    Lack of suitable auto/allografts has been delaying surgical interventions for the treatment of numerous disorders and has also caused a serious threat to public health. Tissue engineering could be one of the best alternatives to solve this issue. However, deficiency of oxygen supply in the wounded and implanted engineered tissues, caused by circulatory problems and insufficient angiogenesis, has been a rate-limiting step in translation of tissue-engineered grafts. To address this issue, we designed oxygen-releasing electrospun composite scaffolds, based on a previously developed hybrid polymeric matrix composed of poly(glycerol sebacate) (PGS) and poly(ε-caprolactone) (PCL). By performing ball-milling, we were able to embed a large percent of calcium peroxide (CP) nanoparticles into the PGS/PCL nanofibers able to generate oxygen. The composite scaffold exhibited a smooth fiber structure, while providing sustainable oxygen release for several days to a week, and significantly improved cell metabolic activity due to alleviation of hypoxic environment around primary bone-marrow-derived mesenchymal stem cells (BM-MSCs). Moreover, the composite scaffolds also showed good antibacterial performance. In conjunction to other improved features, such as degradation behavior, the developed scaffolds are promising biomaterials for various tissue-engineering and wound-healing applications.
    Matched MeSH terms: Oxygen
  13. Recent progress in integrated fixed-film activated sludge process for wastewater treatment: A review
    Waqas S, Bilad MR, Man Z, Wibisono Y, Jaafar J, Indra Mahlia TM, et al.
    J Environ Manage, 2020 Aug 15;268:110718.
    PMID: 32510449 DOI: 10.1016/j.jenvman.2020.110718
    Integrated fixed-film activated sludge (IFAS) process is considered as one of the leading-edge processes that provides a sustainable solution for wastewater treatment. IFAS was introduced as an advancement of the moving bed biofilm reactor by integrating the attached and the suspended growth systems. IFAS offers advantages over the conventional activated sludge process such as reduced footprint, enhanced nutrient removal, complete nitrification, longer solids retention time and better removal of anthropogenic composites. IFAS has been recognized as an attractive option as stated from the results of many pilot and full scales studies. Generally, IFAS achieves >90% removals for combined chemical oxygen demand and ammonia, improves sludge settling properties and enhances operational stability. Recently developed IFAS reactors incorporate frameworks for either methane production, energy generation through algae, or microbial fuel cells. This review details the recent development in IFAS with the focus on the pilot and full-scale applications. The microbial community analyses of IFAS biofilm and floc are underlined along with the special emphasis on organics and nitrogen removals, as well as the future research perspectives.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  14. Fulltext Nanocellulose Reinforced Thermoplastic Starch (TPS), Polylactic Acid (PLA), and Polybutylene Succinate (PBS) for Food Packaging Applications
    Nazrin A, Sapuan SM, Zuhri MYM, Ilyas RA, Syafiq R, Sherwani SFK
    Front Chem, 2020;8:213.
    PMID: 32351928 DOI: 10.3389/fchem.2020.00213
    Synthetic plastics are severely detrimental to the environment because non-biodegradable plastics do not degrade for hundreds of years. Nowadays, these plastics are very commonly used for food packaging. To overcome this problem, food packaging materials should be substituted with "green" or environmentally friendly materials, normally in the form of natural fiber reinforced biopolymer composites. Thermoplastic starch (TPS), polylactic acid (PLA) and polybutylene succinate (PBS) were chosen for the substitution, because of their availability, biodegradability, and good food contact properties. Plasticizer (glycerol) was used to modify the starch, such as TPS under a heating condition, which improved its processability. TPS films are sensitive to moisture and their mechanical properties are generally not suitable for food packaging if used alone, while PLA and PBS have a low oxygen barrier but good mechanical properties and processability. In general, TPS, PLA, and PBS need to be modified for food packaging requirements. Natural fibers are often incorporated as reinforcements into TPS, PLA, and PBS to overcome their weaknesses. Natural fibers are normally used in the form of fibers, fillers, celluloses, and nanocelluloses, but the focus of this paper is on nanocellulose. Nanocellulose reinforced polymer composites demonstrate an improvement in mechanical, barrier, and thermal properties. The addition of compatibilizer as a coupling agent promotes a fine dispersion of nanocelluloses in polymer. Additionally, nanocellulose and TPS are also mixed with PLA and PBS because they are costly, despite having commendable properties. Starch and natural fibers are utilized as fillers because they are abundant, cheap and biodegradable.
    Matched MeSH terms: Oxygen
  15. Treatment of Hospital wastewater with submerged aerobic fixed film reactor coupled with tube-settler
    Khan NA, Bokhari A, Mubashir M, Klemeš JJ, El Morabet R, Khan RA, et al.
    Chemosphere, 2022 Jan;286(Pt 3):131838.
    PMID: 34399260 DOI: 10.1016/j.chemosphere.2021.131838
    In this study, Hospital wastewater was treated using a submerged aerobic fixed film (SAFF) reactor coupled with tubesettler in series. SAFF consisted of a column with an up-flow biofilter. The biological oxygen demand (BOD)5, chemical oxygen demand (COD), nitrate and phosphate were the chosen pollutants for evaluation. The pollutants removal efficiency was determined at varying organic loading rates and hydraulic retention time. The organic loading rate was varied between 0.25 and 1.25 kg COD m-3 d-1. The removal efficiency of SAFF and tubesettler combined was 75 % COD, 67 % BOD and 67 % phosphate, respectively. However, nitrate saw an increase in concentration by 25 %. SAFF contribution in the removal of COD, BOD5 and Phosphate was 48 %, 46 % and 29 %, respectively. While for accumulation of nitrate, it was responsible for 56%, respectively. Tubesettler performed better than SAFF with 52 %, 54 % and 69 % reduction of COD, BOD5 and phosphate, respectively. But in terms of nitrate, tubesettler was responsible for 44 % accumulation. The nutrient reduction decreased with an increase in the organic loading rate. Nitrification was observed in the SAFF and tubesettler, which indicated a well-aerated system. An anaerobic unit is required for completing the denitrification process and removing nitrogen from the effluent. The better performance of tubesettler over SAFF calls for necessitates extended retention time over design criteria. Further studies are beneficial to investigate the impact of pharmaceutical compounds on the efficiency of SAFF.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  16. Comparative performance of Scirpus grossus for phytotreating mixed dye wastewater in batch and continuous pilot subsurface constructed wetland systems
    Almaamary EAS, Abdullah SRS, Ismail N', Idris M, Kurniawan SB, Imron MF
    J Environ Manage, 2022 Apr 01;307:114534.
    PMID: 35065382 DOI: 10.1016/j.jenvman.2022.114534
    Dye is one of the pollutants found in water bodies because of the increased growth of the textile industry. In this study, Scirpus grossus was planted inside a constructed wetland to treat mixed dye (methylene blue and methyl orange)-containing wastewater under batch and continuous modes. The plants were exposed to various concentrations (0, 50, 75, and 100 mg/L) of mixed dye for 72 days (with hydraulic retention time of 7 days for the continuous system). Biological oxygen demand, chemical oxygen demand, total organic carbon, pH, temperature, ionic content, and plant growth parameters were measured. Results showed that S. grossus can withstand all the tested dye concentrations until the end of the treatment period. Color removal efficiencies of 86, 84, and 75% were obtained in batch mode, whereas 90%, 85%, and 79% were obtained in continuous mode for 50, 75, and 100 mg/L dye concentrations, respectively. Fourier-transform infrared analysis confirmed the transformation of dye compounds after treatment and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analysis showed that most of the intermediate compounds were not absorbed into plants but adsorbed onto the surface of the root structure.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  17. A sequential treatment of intermediate tropical landfill leachate using a sequencing batch reactor (SBR) and coagulation
    Yong ZJ, Bashir MJK, Ng CA, Sethupathi S, Lim JW
    J Environ Manage, 2018 Jan 01;205:244-252.
    PMID: 28987987 DOI: 10.1016/j.jenvman.2017.09.068
    The increase in landfill leachate generation is due to the increase of municipal solid waste (MSW) as global development continues. Landfill leachate has constantly been the most challenging issue in MSW management as it contains high amount of organic and inorganic compounds that might cause pollution to water resources. Biologically treated landfill leachate often fails to fulfill the regulatory discharge standards. Thus, to prevent environmental pollution, many landfill leachate treatment plants involve multiple stages treatment process. The Papan Landfill in Perak, Malaysia currently has no proper leachate treatment system. In the current study, sequential treatment via sequencing batch reactor (SBR) followed by coagulation was used to treat chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), total suspended solids (TSS), and colour from raw landfill leachate. SBR optimum aeration rate, L/min, optimal pH and dosage (g/L) of Alum for coagulation as a post-treatment were determined. The two-step sequential treatment by SBR followed by coagulation (Alum) achieved a removal efficiency of 84.89%, 94.25%, 91.82% and 85.81% for COD, NH3-N, TSS and colour, respectively. Moreover, the two-stage treatment process achieved 95.0% 95.0%, 95.3%, 100.0%, 87.2%, 62.9%, 50.0%, 41.3%, 41.2, 34.8, and 22.9 removals of Cadmium, Lead, Copper, Selenium, Barium, Iron, Silver, Nickel, Zinc, Arsenic, and Manganese, respectively.
    Matched MeSH terms: Biological Oxygen Demand Analysis
  18. Fulltext Parametric Studies of Titania-Supported Gold-Catalyzed Oxidation of Carbon Monoxide
    Chong S, Yang TC
    Materials (Basel), 2017 Jul 05;10(7).
    PMID: 28773110 DOI: 10.3390/ma10070756
    This paper remarks the general correlations of the shape and crystallinity of titanium dioxide (TiO₂) support on gold deposition and carbon monoxide (CO) oxidation. It was found that due to the larger rutile TiO₂ particles and thus the pore volume, the deposited gold particles tended to agglomerate, resulting in smaller catalyst surface area and limited gold loading, whilst anatase TiO₂ enabled better gold deposition. Those properties directly related to gold particle size and thus the number of low coordinated atoms play dominant roles in enhancing CO oxidation activity. Gold deposited on anatase spheroidal TiO₂ at photo-deposition wavelength of 410 nm for 5 min resulted in the highest CO oxidation activity of 0.0617 mmol CO/s.gAu (89.5% conversion) due to the comparatively highest catalyst surface area (114.4 m²/g), smallest gold particle size (2.8 nm), highest gold loading (7.2%), and highest Au⁰ content (68 mg/g catalyst). CO oxidation activity was also found to be directly proportional to the Au⁰ content. Based on diffuse reflectance infrared Fourier transform spectroscopy, we postulate that anatase TiO₂-supported Au undergoes rapid direct oxidation whilst CO oxidation on rutile TiO₂-supported Au could be inhibited by co-adsorption of oxygen.
    Matched MeSH terms: Oxygen
  19. Fulltext Draft Genome Sequence of Comamonas testosteroni R2, Consisting of Aromatic Compound Degradation Genes for Phenol Hydroxylase
    Azwani F, Suzuki K, Honjyo M, Tashiro Y, Futamata H
    Genome Announc, 2017 Sep 07;5(36).
    PMID: 28883136 DOI: 10.1128/genomeA.00875-17
    Comamonas testosteroni strain R2 was isolated from a continuous culture enriched by a low concentration of phenol-oxygenating activities with low Ks values (below 1 μM). The draft genome sequence of C. testosteroni strain R2 reported here may contribute to determining the phenol degradation gene cluster.
    Matched MeSH terms: Reactive Oxygen Species
  20. Fulltext Temperature-Driven Structural and Morphological Evolution of Zinc Oxide Nano-Coalesced Microstructures and Its Defect-Related Photoluminescence Properties
    Lim K, Abdul Hamid MA, Shamsudin R, Al-Hardan NH, Mansor I, Chiu W
    Materials (Basel), 2016 Apr 20;9(4).
    PMID: 28773425 DOI: 10.3390/ma9040300
    In this paper, we address the synthesis of nano-coalesced microstructured zinc oxide thin films via a simple thermal evaporation process. The role of synthesis temperature on the structural, morphological, and optical properties of the prepared zinc oxide samples was deeply investigated. The obtained photoluminescence and X-ray photoelectron spectroscopy outcomes will be used to discuss the surface structure defects of the prepared samples. The results indicated that the prepared samples are polycrystalline in nature, and the sample prepared at 700 °C revealed a tremendously c-axis oriented zinc oxide. The temperature-driven morphological evolution of the zinc oxide nano-coalesced microstructures was perceived, resulting in transformation of quasi-mountain chain-like to pyramidal textured zinc oxide with increasing the synthesis temperature. The results also impart that the sample prepared at 500 °C shows a higher percentage of the zinc interstitial and oxygen vacancies. Furthermore, the intensity of the photoluminescence emission in the ultraviolet region was enhanced as the heating temperature increased from 500 °C to 700 °C. Lastly, the growth mechanism of the zinc oxide nano-coalesced microstructures is discussed according to the reaction conditions.
    Matched MeSH terms: Oxygen
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